diff --git a/src/Network/Routing/Dict/Internal.hs b/src/Network/Routing/Dict/Internal.hs
--- a/src/Network/Routing/Dict/Internal.hs
+++ b/src/Network/Routing/Dict/Internal.hs
@@ -174,7 +174,7 @@
   Ix' i k (k  := v ': kvs) = NotInDicrionary i
   Ix' i k (k' := v ': kvs) = Ix' (i + 1) k kvs
 
-type Ix = Ix' 0
+type Ix k kvs = Ix' 0 k kvs
 
 type Index = NotInDicrionary
 
diff --git a/web-routing.cabal b/web-routing.cabal
--- a/web-routing.cabal
+++ b/web-routing.cabal
@@ -1,5 +1,5 @@
 name:                web-routing
-version:             0.4.1
+version:             0.4.2
 synopsis:            simple routing library
 -- description:         
 license:             MIT